Israeli forces injured two Palestinians after they struck six sites belonging to Hamas and Islamic Jihad.

The attack was in response to a volley of mortar fire from Palestinian militants that same afternoon that was aimed at Israeli army forces currently building an enormous underground wall and anti-tunnel barrier on the border with the Gaza Strip.

According to Gaza’s Health Ministry, Israeli forces injured two Palestinians after the Israeli army struck six sites belonging to Hamas and Islamic Jihad.

Thursday’s attack by Palestinian groups was likely in retaliation for Israel’s destruction a month ago of a tunnel built by Islamic Jihad that snaked from Gaza and into Israel, said Lt. Col. Jonathan Conricus, a spokesman for the Israeli military.

Daud Shehab, the leader of Islamic Jihad in Gaza, said the “Zionist aggression” was an attempt to distract from the killing of a Palestinian man in the West Bank by Israeli settlers earlier that day.

“The Palestinian resistance has the full right to defend and respond to this dangerous escalation,” he said. “The occupation bears responsibility.”

The barrier, first proposed in 2014 during Israel’s assault on Gaza during the IDF’s Operation Protective Edge, will be a 20-mile concrete wall, equipped with sensors to record any digging activity.

Tunnels have been used by militant Palestinian groups to fire rockets into Israel, in an act of resistance against Israeli occupation. They were used by Hamas in this way in 2014, during the 50-day Israeli Forces’ campaign against Gaza, which left at least 2,251 Palestinians dead, including women and children.